The metal-working industry, in order to accomplish shaping processes on metals, no matter whether they are made by cutting or non-cutting, needs coolants which facilitate the shaping processes and which, in particular, are in a position to eliminate the heat energy occurring, and to simultaneously and subsequently protect the shaped metal from corrosion.
As is well known, such agents are generally called cooling--cutting compounds or else cooling lubricants. The development of these cooling--cutting compounds was particularly rapid during the past decade, because of the general tendency for the automation of the finishing processes, whereby this development led to products which in their essence and composition may be defined as colloid-dispersed systems of non-saponifiable mineral oils in mixture with surface-active substances in water.
As a result of automating the production within the metal-working plants, it has become necessary to depart from the formerly customary use of pure mineral oil emulsions, which had been produced from petroleum sulfonates and mineral oils, since these mineral oil emulsions no longer satisfied the rising demands. On the one hand, these mineral oil emulsions, because of their high content of mineral oil, had only a poor or unsatisfactory cooling effect. On the other hand, these mineral oil emulsions, because of their low capacity for dilution with water, also had only a poor or unsatisfactory corrosion protection behavior. A third disadvantage of these mineral oil emulsions was their low resistance against micro-organisms, resulting in the undesirable formation of decaying substances, odorous annoyances and a high strain on the environment.
The development of better cooling-cutting agents which resulted in less of a strain on the environment and contained less mineral oil led to the use for the first time of complex soaps of ethanol amines with natural fatty acids, which were obtained by special processes under the influence of boric acid at temperatures between 230.degree. and 200.degree. C. These new cooling, cutting agents were used with great success in the metal-working industry. For example, in metal processing or metal forming plants, in which the former coolants could be kept only a few weeks with the addition of preservatives, operating lifetimes of 80 weeks and more achieved with the above described novel products, without there being any need of adding preservatives. This advantage alone provides a tremendous decrease in the costs, and enables a manifold increase in the effects of automation. Furthermore, the skin allergies of the workers, caused by the preservatives used, disappeared completely when the above described novel products were substituted.
It was further observed that using the above mentioned novel cooling-cutting agents, (representing colloidal-disperse systems), allowed one to carry out cutting operations on highly alloyed steels for airplane turbines; these operations not being achieved up to that time and which were not even considered possible.
Therefore, these new, above described cooling-cutting agents have been found to be very satisfactory for numerous applications.
However, in considering particular technical applications, it became apparent that certain disadvantages still exist for certain areas of usage which could not be eliminated by the use of the above described prior art cooling-cutting agents.
The reason for the problems with the prior art agents is that all known fatty acids form lime soaps which lead to deposits. These deposits in turn, together with the mineral oil coming from the machines, lead to residues. These residues are not removable or removable only with great difficultly because of their insolubility in water.
These problems at first seem insignificant but lately they have acquired extraordinary importance in practice, and to be sure, expecially in the case of machines and finishing processes that are controlled numerically. Their manufacturing output may be interrupted or even stopped by the adhesion of a small metal splinter to the slideways.
Furthermore, the precipitated lime soaps, which may be deposited in the supply line systems, form a nutrient medium for microorganisms. These microorganisms consume the organic components of the lime soaps and leave insoluble calcium oxide or insoluble calcium carbonates behind. These lime deposits, which then solidify in the pipe line systems, lead to the pipe lines growing shut radially from the outside of the pipe lines towards the inside and eventually plugging up the pipe lines completely.